Why would I suggest open source apps over those 'freemium' proprietary apps available for Windows? Simple: being open source you can trust them because you can audit the code. And unlike many proprietary free apps, there is no adware or malware bundled with them to exploit or monetize a user.

Video needs no introduction. It is the most powerful media player around. And since Microsoft has stripped off DVD playback capability and charges something around $15 for the player, VLC becomes even more interesting for those Windows users who still want to run DVDs.

VLC is capable of playing virtually every media format under Windows 10, without having to install any additional codecs. Plus, VLC can do much more than simple playback.

While VLC is capable of playing music, it's not optimized for that job. If you are looking for an open source music app, Clementine is the one you want. And it is cross platform so you can run it on Linux, Windows and Mac OS X.

It has a neat interface and can do much more than playing music. One of the reasons I like Clementine is that it supports network playback. Since I have multiple systems that run different operating systems, it's physically not possible for me to plug-unplug my few terabytes or hard drives from one system to another, or to keep duplicate copies of the same files. So I run a central file server and share files from one location to all these device using Samba share. Clementine allows me to connect to Samba server and play tracks directly from the networked drive.

Clementine has many more features that far exceed those found on Windows 10's built-in media player.

Both Clementine and VLC are capable of playing various media formats, but you may still need to convert media files to make them playable on mobile devices. For this you need a media converter. There are many media converters for Windows, but they are either paid or bloated with adware or other software that can pose a risk to your Windows system, so using an open source tool is the best solution. Handbrake is by far the best media converter that also supports batch-processing (if you have more than one file to convert).

Thunderbird, hands down, is the best email client across operating systems. It is developed by Mozilla Corporation, which also develops Firefox. Users can add more functionality to Thunderbird with the use of add-ons: You can get calendar integration, chat support and much more. One of the greatest advantages of Thunderbird is 'portability': If, for example, you are dual booting between Linux and Windows you can create a profile and store your mail in a shared location and Thunderbird will remain synced between the two operating systems.

Firefox, like Thunderbird, is developed by the Mozilla Corporation and was the most popular web browser before Google Chrome came along. You can add more functionality to Firefox using add-ins or plugins. And there is a built-in feature of Firefox that can sync your passwords, bookmarks and other stuff securely.

While Firefox is fully open source, Google Chrome is not: It is based on the fully open source Chromium browser. Both Chrome and Chromium are available for Windows users. Chrome may be a better choice if you frequent some Flash-based sites because Google is working on their own 'secure' plugin for Adobe Flash. Instead of installing the notoriously insecure Adobe Flash plugin on your system, it would be safer to use Chrome. Just like Firefox, you can add more functionality to Chrome through Web Apps.

Adobe Photoshop is the best image editing software around, but not everyone needs or can afford it. There is a free and open source app called GIMP that does a great job of image editing. While I do have an Adobe Creative Cloud subscription and use Photoshop and Lightroom for professional work, I heavily use GIMP on my Linux systems and I am pretty happy with it. The UI of GIMP is quite similar to that of Photoshop, which makes it easy to switch between the two apps. You can expand the features of GIMP by using plugins, scripts and extensions. Try it out and you may realize that it's what you had been looking for.

If you are a painter or graphic artist, there is nothing that beats the open source application Krita. Being developed by the KDE Community, Krita also doubles as image editing software, though its core competence remains in 'drawing, sketching, or creating works or art.' Krita has great support for touch-based devices through Krita Sketch, a version optimized for touch devices. Krita is overflowing with features, many more than I can mention here. Check out the Krita page for a full list of features.

You don't need to spend hundreds of dollars per year to use a decent office suite. LibreOffice is a great free and open source office suite. Unlike Microsoft Office, with LibreOffice your documents won't be locked into a non-standard format: LibreOffice uses an ISO approved standard format to store your documents. LibreOffice comes with an entire suite of applications including Spreadsheets, Presentation and much more.